Telephone-transmitter.



' I'. GOTTSCHALK.

TELEPHONE TRANSMITTER.

. APPLICATION FILED 1113.16, 1912.l

pyg@ Patented Deo. 3, 1912i;

2 SHEETS-SHEET l.

F. GOTTSGHALK.

TELEPHONE TRANSMITTER.

APPLICATION FILED PEB. 1 6, 1912.

1,045,968, Pandnec.3,'1912j 2 SHEETS-SHEET 2.

UNIE

FELIX GOTTSGHALK, 0F NEW YORK, N. Y.

TELEPHONE-TRANSMITTER.

Specification of Letters Patent.

Patented Dec. 3, 1912.

Application led February 16, 1912. Serial No. 677,887.

To all whom 'it may concern:

Be it known that I, F nLiX GoT'rsoHALK, a citizen of the United States, residing at New York, in the county of New York and State of New York, have invented certain My invention relates to telephone transmitters and consists of the use of a sound receiving diaphragm of rolled or tempered metal having an initial stress, in combination with an improved form of water and air-tight casing, the diaphragm being securely clamped thereto at its periphery in a stretched condition, with the result that a. gain in transmitting eiiciency is secured.

My invention relates more particularly to the form of diaphragm employed, in com bination with a casing so disposed that the entire back of the diaphragm is covered by said casing which is so disposed as to eliminate practically all of the air space exceptthat occupied by t-he transmitter cell. This construction results in an easily and cheaply assembled instrument, in which means for stretching thc'diaphragm to have same under tension is eliminated. There are other advantages which will be hereinafter described and claimed.

In the accompanying drawings: Figure 1,

'is a front view of a transmitter embodying this invention, with portions broken away.

Fig. 2, is a cross-sectional view through the` is placed the sound receiving diaphragm@` which is separated from'the casing by smtable packing 3 of such thickness that the space between the diaphragm and casing is reduced to a minimum. The diaphragm used in an instrument of this type must be of metal and is preferably rolled like phosphor bronze, or tempered like steel so' as to possess an initial inherent stress, thereby eliminating the necessity of employing stretching means when the diaphragm is in place.

Heretofore metallic diaphragms for telephone transmitters have usually been constructed from ferro-type iron or aluminum and in this construction required the vuse of damping springs, clamps or pins, either on the outside or inside of the diaphragm, thus preventing free vibration. I eliminate devices of this nature, by my improved diaphragm, which, being rrnly secured only at the periphery, is free to vibrate, like a drumhead.

To securely attach the diaphragm to the casing I employ a row of screws indicated at 4.- and "5, which securely hold the clamp ring 6 on the diaphragm as shown; but, if desired, any suitable alternate method of clamping may be employed. For instance, with diaphragms of certain thicknesses it is desirable to bevel the edge of the casing 1 as shown in Fig. 2 andv to slightly dish the diaphragm to conform to said bevel, and to then employ the ring with inwardly beveled edge as shown at 6, Fig. 2. The casing 1 has a rearwardly projecting Harige 7, having an aperture 8 therein, in which is placed a c'ell 9 of any suitable type., The cell illustrated in `the drawing is of aV well known form having its insulated front electrode toward the diaphragm and its frame electrode toward the rear of the cell, the stem 10 being a part of the latter.

Any suitable manner of supporting the cell and closing the chamber 8 against the ingressof air or moisture may be employed. The preferred arrangement is shown in the drawing and I consider same to be a separate invention for which I have applied for Letters Patent Serial Number 677,112, the title of said application being Transmitter casings but I disclose this .arrangement here, as 'it is the preferred form for use with the transmitter herein shown.

The stem 10 is placed in the recessed terminal piece 11, which'is insulated from the tiange 7 by packing shown at 12 and by suitably bushed screws 13 and 14. The stem is held in place by the adjusting screw 1 5. To prevent the entrance of moisture or air I provide the packing 16 and the screw 17,

thereby closing the opening above 15.

18 is a connecting cord or wire which is held in the terminal piece 11 by suitable means such as the screw 19.

The front electrode is connected to the diaphragm by means of a spider 20 having two or more legs, the outer ends of which touch the diaphragm at interperipherical points.

For mounting the transmitter on the telephone instrument I provide the usual back shell 21 and inclose the front of the instrument with (the guard 22, having suitable apertures to permit t-he sound waves to impinge on the diaphragm. This guard is so shaped that it laps 'over the back shell as shown, thereby permitting the same screws 28 and 24; to hold guard, back shell, and transmitter together, thus eliminating all but one joint or seam 25 at the outside of the instrument.

In use, the transmitter being placed in a suitable circuit, one side of which is connected to the casing and the other side to the insulated piece 11, sound waves impinging on the diaphragm will be transmitted to the resistance cell, thereby varying the current flowing through same. It ywill be observed that the workingparts of the instrument are completely inclosed; and. the casing l being inr one piece, great rigidity is secured, all seams being eliminated except those that are packed.

1. In a telephone transmitter, a one piece metallic sound receiving diaphragm rolled or tempered to possess initial tension, means for clamping said diaphragm at substantiallyl all points on its periphery to a casing, an insulated cell support carried by said casing. a resistance cell carried bv said support, and 'means for conducting vibrations from said diaphragm to said cell.

2. In a telephone transmitter. a perforated metallic guard, a metallic sound receiving diaphragm back of said guard having substantially all of its free vibrating surface yexposed to said perforations, a casing supporting said diaphragm and having a flanged portion lying adjacent to and in a plane with the rear face of said diaphragm, an aperture in said flange at right angles to the plane of its greatest diameter, a cell support closing the rear of said aperture, insulation between said cell support' and the casing, transmitter mechanism inclosed in the chamber formed by said diaphragm, the cell support, and its casing, a back shell supported on a flange in said casing, and means for supporting said guard by said back shell.

8. In a telephone transmitter, a cell member, a casing surrounding the cell, a rearwardly extending flange on said casing forming a support for a back shell, a metallic support for the cell mounted on and inhaving a flange at its outer edge projecting 1 rearwardly to form a support for an outer.

shell, a central aperture in said casing, a cell in said aperture, an electrode in said cell insulated therefrom and connected with the diaphragm, a stem projecting rearwardly from said cell, a support for said stem clos ing said aperture and insulated from said casing, an adjusting screw in said support, and a circuit terminal carried thereby.

In testimony whereof I hereuntoatlix my signature in the presence of two witnesses.

FELIX GOTTSCHALK. j Witnesses 1 H. G. TORREY, CHARLES TAYLOR. 

